Station selector mechanism



Sept. 5, 1933. B. B. BIRD 1,925,651

STATION SELECTOR MECHANISM Filed April 8, 1929 3 Sheets-Sheet l I Q ,5 Z5 J r I \I 4 r n i J l.l ,6 47 a H.

INVENTOR A TTOR/VEY Sept. 5, 1933. B. B. BIRD STATION SELECTOR MECHANISM 5 Sheets-Sheet 2 Filed April 8, 1929 11v VENTOR fizz/Way 5. fiz'rd.

A TTORNIE Y Sept. 5, 1933. BIRD 1,925,651

STATION SELECTOR MECHAN-ISM FiledApril 8, 1929 3 Sheets-Sheet 5,

g L ,fflllnllow 22 n ,l\ \V II A w 1\ x I), Y WWI W A I/TORNE'Y Patented Sept. 5, 1933 1,925,651 STATION SELECTOR MECHANISM Burney B. Bird, Los Angeles, Calif. 7 Application April 8, 1929. Serial No. 353,473 12 Claims. (01. 250-20) My invention relates to radio receiving sets, and particularly to mechanisms for securing predetermined adjustments of the tuning instruments thereof to automatically obtain any preselected broadcasting station within the rangeof the set.

In station selector mechanisms of this character, as heretofore proposed, the parts of the mechanisms have been such as to preclude that a micrometric adjustment of the tuning instruments necessary to secure sharp tuning of the set to obtain reception of volume and clarity. Further, in such mechanisms, what provision is made in additional adjustment of the individual adjusting units for the respective stations to compensate for variation in wave length of any particular broadcasting station, or because of adverse atmospheric conditions, is such that the additional adjustment when once made, isper: manently maintained so that if a particular station returns to its designated wave length, or where atmospheric conditions return to normal, the additional adjustment is no longer necessary to bring 'in that station with maximum clarity and volume. Also, in such mechanisms, when operating a mechanism to select a particular station, where it is necessary to make large adjustments of the tuning instruments, the radio set remains in a receptive state during such adjustments, thus bringing in otherstations within the range of adjustment, and although momentarily, nevertheless, producing objectionable noise and operating injury to the delicate parts of the set.

It is a purpose of my invention to provide a station selector mechanism which is characterized by the high degree of accuracy with, which the tuning instruments of a receiving set may be adjusted to select any particular station with the maximum clarity and volume of which the set is capable and with a minimum consumption of current. Not only does my mechanism initially possess this characteristic, but it continues to do so indefinitely, as distinguished from previous mechanisms-in which what initial degree of accuracy in adjustment is attained, is soon lost by reason of the play soon developed by the component parts of the mechanism.

It is also a purpose of my invention to provide a station selector mechanism in which that additional adjustment necessary to select a particular station which is not broadcasting on its prescribed wave length, or where variation in wave length occurs because of atmospheric or static conditions, it is attained only temporarily, or as long as the set remains tuned to that particular .station, so that should that station be again selected at some future time and received on its prescribed wave length, no additional adjustment of the tuning instruments is required, because, those parts of the mechanism necessary to such additional adjustments have been automatically restored to a neutral position.

A further purpose of my invention is the provision in a station selector mechanism of a 55 means acting upon operation of any of the adjusting units of the mechanism to render the receiving set inactive for the purpose of reception, and in order that when any one of the adjusting units of the mechanism is being manipulated to select a particular station, no other stations can be received, thereby eliminating objectionable noise incident to such selection, and protecting the delicate parts of the set against injury.

I will describe only one form of station selector mechanism embodying my invention and will then point out the novel features thereof in claims.

In the accompanying drawings:

Fig. 1 is a view showing in top plan one form of station selector mechanism embodying my invention in applied position to the tuning instruments of a radio receiving set.

Fig. 2 is a vertical sectional view taken on the line 22 of Fig. 1. m

Fig. 2 is a semi-diagrammatic perspective view illustrating certain of the cams of the mechanism shown in the preceding views.

Figs. 3 to 6 are enlarged sectional views taken on the lines 3-3, 44, 55, 6-6 respectively, of Fig. 1. I

Fig. 7 is an enlarged vertical sectional view taken on the line 7-7 of Fig. 2.

Fig. 8 is a vertical sectional view taken on the line 8-8 of Fig. 7.

In Figs. land 2 is shown a cabinet K without its top, and in which is contained the tuning instruments of a-radio receiving set, and any other 1 parts of the set which the cabinet may accommodate in addition to the station selector mechanism embodied in'my invention. The tuning instruments-are here illustrated as a plurality of condensers designated at C which are of conventional form in that they are composed of stator plates p and rotor plates 11, the latter being fixed to a shaft s journaled in a frame f and rotatable by means of a drum D, the periphery of which is calibrated in the usual manner. The drum D and the condenser C are shown as manually operable by a shaft s projecting through the front wall ,of the cabinet and provided with a knurled head h which is adapted to be manually rotated and to thereby efiec rotation of the drum? The station selector mechanism here illustrated embodies a. shaft 15 which, in the present instanc is shown as a continuation of the shaft 8, the free extremity of the shaft 15 being journaled in a frame 16. On the shaft 15 are mounted a plurality of cams, each having a hub 17 through which the shaft extends and atubular extension 18 (Fig. 3) projecting rearwardly from the hub and in which is received a locking member 19 of wood, metal or any other suitable material, which is engaged by a screw 20 threaded in the extension for forcing the inner end of the member 19 against the shaft 15 with such a degree of security as to lock the hub to the shaft,

tute a means for locking its respective cam in any adjusted position circumferentially on the shaft for a purpose to be described hereinafter, as it will be understood that by relieving the member 19 of inward pressure by outward adjustment of the screw 20, the hub 1'? is free to be rotated to any adjusted position circumferentially on the shaft and to effect a corresponding adjustment of the respective cam. Once this adjustment is secured, the member 19 may again be brought into locking relation to the shaft 15 by readjustment of the screw 20;

Each cam is adapted to be manually actuated to rotate the shaft 15 a predetermined distance, by the provision of a lever 21 fulcrumed on a shaft 22 journaled at one end in a bearing 23 on a bracket 24, and at the other end in the frame 16. As illustrated to advantage in Figs. 1 and 2, each lever 21 is provided at its inner end with a sleeve 25 which constitutes a hub for mounting the lever on the shaft 22. The lever is of such length as to extend to a corresponding slot in the front wall of the cabinet K where it is provided with a head 26, adapted to be engaged by the finger of the operator for depressing the lever. The slot of the cabinet is lined by a metal frame 27, which in addition to {arm tecting the walls of the slot, provides an abutment for limiting movement of thelever in either direction, and thus defining the uppermost or normal position of the lever. The lever is maintained in normal position by means of a spring 28 secured to an angle bar 29 fixed to the inner side of the front wall of the cabinet. Each lever is'provided with a slot 30 (Fig. 1) in which the corresponding cam is received. Mounted within the slot is a wiping roller 31, adapted for engagement with the correspondingcam, whenthe lever is moved downwardlyfrom its normal po sition, and to thereby rotate the cam, which in turn, effects rotation of the shaft 15, It is important to note, that in the normal position of the lever 21 as defined by the upper end of the 'slot frame 2'? the wiping roller 31 is out of con-- tact with the corresponding cam and its hub.

:In the present instance I have shown the mechanism as embodying six cams and six levers,

each cam and its corresponding lever together with the parts carried thereby constituting one adjusting unit of the mechanism, and each adjusting unit constitutes a means acting when operated to produce a predetermined adjustment mas er the construction and positioning of the cam. and

thus securing a predetermined adjustment of the condensers C. It will therefore be evident, that to obtain various adjustments of the condensers C, the shaft 15 must be rotated different distances and in either direction, and I will now describe the construction and arrangement ofthe several cams by which the different adjusting units act when operated to secure the different adjustments of the condensers necessary to obtain the preselected broadcasting stations.

The several cams have the common structural characteristic of being cordiform in outline, to provide cordiform cam surfaces with, which the wiping rollers 31 are adapted to con-'-- tact when the levers 21 are actuated. Referring to Figs. 2 and 2, it will be seen that the first cam to the right indicated at 32 has its hub disposed inwardly with respect to one side of the cam,and

as a consequence in the normal position of the cam as illustrated, its cam surfaces is so disposed I that upon actuation of the corresponding wiping roller, the cam will be rotated in a counterclockwise direction to impart a corresponding movement to the shaft 15. During this operation, the roller 31 in its initial downward movement first wipes the curved portion of the cam surface, and then it proceeds to,wipe the linear portion of the cam surface, the roller finally reposing in the point or apex of the cam, as-illustrated in dash lines in Fig. 6. In consequence of this operation, the cam in its final position, as illustrated in dash lines in Fig. '6 is. moved 180 from its normal upright position, and this re-' sults in a corresponding movement of the "rotor plates .11 of the condensers C. In condensers of the type illustrated the range in movement of the rotor plates is 130. Consequently, assuming that it is desired to move the condenser plates through their complete range of adjustment, such adjustment can be instantly effected by operation of that lever 21 for the cam 32. To move the condenser plates 1) in the opposite direction and through the entire range of adjustment, I provide a cam 33, which is that cam at the extreme left of the group, and which is identical in construction to the cam 32 but reversed in its position on the shaft 15 so that when the corresponding lever 21- is depressed, the wiping roller will engage the inner surface of the cam, and thus cause rotation of the cam in a clockwise direction as when viewed in Fig. 2. Thus, the adjusting units defined by the earns 32 and 33 are those units adapted to be operated for effecting movement of the rotor plates. of the I condensers for securing maximum adjustment thereof throughout their complete range of H movement in either direction.

Those adjusting units between the two endmost units have cams designated at 34. and these cams have cam surfaces of similar cordiform outline, although they are secured at different positions circumferentially on the'shaft 15, in order that their apexes occupy different positions circumferentially, and in consequence of which,

they will act when operated to rotate the shaft 15 various degrees,- and thus secure various predetermined adjustments of the condensers between the two maximum adjustments, as defined by the operation of the cams 32 and 33. The setting of the cams 34 to secure these intermediate and preselected adjustments of the condenser C will be manifest from the preceding description of the means for locking any one cam in adjusted position on the shaft 15. In practice, it is desirable that the extensions 18 be so formed on the cams, that, with the cams properly adjusted on the shaft 15 andthe latter in normal position, all of the extensions are positioned vertically to facilitate manipulation of the screws 20. V

It is important to note that the construction of the several cams 32, 33 and 34, and their positioning on the shaft 15, is such, that irrespective of the circumferential position of the shaft 15 at any time, any one of the cams may be operated by the corresponding lever to effect a new adjustment of the condensers, and that, under the action of the spring 28, the lever is free to return to its normal elevated position without disturbing a previous adjustment of the corresponding cam. In this manner, the several adjusting units provide a means operable to effect any preselected adjustment of the condensers and to maintain such adjustment when once secured.

It frequently occurs that a broadcasting station is not operating on the precise allotted wave length, or that atmospheric or static conditions are such as to prevent clear and voluminous reception. Ineither event it is necessary in my mechanism to make a further small adjustment of the condensers. Such additional adjustment is effected by an adjustment of the cam for that particular adjusting unit, and this adjustment of the cam is. produced by longitudinal adjustment of the corresponding lever 21. For this purpose, the shaft 22 is provided with a cam 35 (Fig, 7) upon which the hubs 25 of the levers 21 are mounted. Keyed to one end of the shaft 22, is an arm 36 rising to one side of a bracket 37, the latter being secured to the inner side of the cabinet and provided with a pair of arcuate slots 33 longitudinally aligned but having their confronting ends spaced apart at a point corresponding to the normal upright position or" the arm 36. A coil spring 39 depends from the bracket 37, the extremities of the spring being bent at right angles to provide extensions 40 which extend through the slots 33 and to the opposite side of the arm 36 where they are again bent to retain the extensions against displacement from the slots. The action of the spring 39 is such, that the extensions 40 are urged to the confronting ends of the slots, the arm 36 being disposed between such extensions but not engaged thereby, that is when the arm is in its normal position. Through the provision of a rod 41 and a handle 42, the latter projecting from the front side of the cabinet K, each arm 36 may be manually moved in either direction from its normal position to rotate the cam 35, in one direction or the other. By such rotation of the cam, the hubs 25 are actuated to move the levers longitudinally in one direction or the other depending upon the direction of rotation of thecarn. In this manner, any one lever 21 may be adjusted longitudinally to cause such movement of the corresponding roller 31 as to efiect the required adjustment of the corresponding cam, and to thereby in turn rotate the shaft 15 the required amount to produce the desired adjustment of the condensers C. Of course, it will be apparent that by rotation of the cam shaft 35 all of the levers 21 are adjusted, but in practice, only one lever is adjusted at a time to secure the necessary fine adjustment of the respective cam to attain the required adjustment of the condensers for accurately tuning in a particular station. It will be noted that when the roller 31 is at the apex of the cam as illustrated in dash lines of Fig. 6, its periphery engages the opposite inner sides of the cam, but not, the extreme apex of the cam; Consequently, with each operation of the corresponding lever, the roller moves to the same extreme position at the apex of the cam so as to rotate the cam exactly the same amount. This insures the same degree of adjustment of the condensers each time the same-adjustingunit is operated. It also provides a positive operative connection between the cam and the lever to secure an adjustment of the former by a longitudinal adjustment of the latter through rotation of the cam 35, as has been described.

An important feature of the just described mechanism, is the mounting of the spring 39 and the manner in which it is associated with the arm 36. Although the spring 39 is normally under tension, and its tension may vary, it nevertheless at all times operates to return the arm 36 to the same normal position. This result is effected by reason of the fact thatv in the nor mal position of the arm, the spring'extensions 40 are prevented from contacting with the arm because of the positioning of the inner ends of the slots 38. This function is important because as a result thereof, the cam 35 is always restored to the same normal position so as not to disturb the normal condenser adjustments obtained by actuation of the adjusting units.

For rendering the receiving set inoperative during theoperation of any one adjusting unit, and for the purpose of preventing reception of stations other than the station selected, and to thereby eliminate objectionable noise and prevent injury to the delicate parts of the set, as previously expressed herein, I provide a circuit controller or switch for disrupting the circuit of the set co-incident with the depressing movement of any one of the levers '21. This circuit controller is illustrated in Fig. 4 as comprising a contact arm 43, secured to the under side of an angle bar 44, the latter being mounted for rocking movement on the shaft 22 by the provision of ears 45 loosely embracing the shaft. The bar 44 is yieldably urged to a position in which the contact arm 43 engages a lower stationary contact 46, a spring 47 being provided for the purpose and connected at its lower end to a bracket 48 and at its upper end to an arm 49 secured to the under side of the bar 44, all as clearly shown in Fig. 5. In this urged position of the bar 44, its rising portion engages the under side of all of the levers 21 so that when any one of the levers is depressed, the bar is rocked about the shaft 22 as a center, to assume the position illustrated in dash lines in Fig. 4, and in which, the arm 43 engages an upper stationary contact 50. The two contacts 46 and 50 are electrically connected to each other, as illustrated in Fig. 4,

while the contacts 43 and 46 or the contacts 43 345 ception. However, when the contact arm 43 is out of engagement with the contacts d6 and 50, the circuit is disrupted. This condition exists upon initiating depressing movement of any of the levers 21. but when the lever reaches its lowermost position, the switch is again closed and the current re-established. Thus, during movement of any one of the adjusting cams 32, 33 or 34, the circuit of the receiving set is disrupted so as to prevent the reception of stations incident to the selection of a predetermined station.

Although I have herein shown and described only one form of station selector mechanism embodying my invention, it is to be understood that various changes and modifications may be made herein without departing from the spirit of the invention and the spirit and scope of the appended claims.

I claim: w

1. In a station selector mechanism for radio receiving sets,'a cam adapted for operative connection to a tuning instrument, a member yieldably urged to one extreme position and manually movable to another extreme position, an operative connection between said cam and member for movingthecam to a predetermined position, said operativeconnection being so correlated with respectto the cam and member as to permitthe meinber toireturn' to its urged position withoutdisturbing-the position to which said cam has "been moved, and means for adjusting said member when occupying the last mentioned extreme position to efiect an adjustment of the cam in its predetermined position.

2. In a station selector mechanism, a shaft, a cam having a hub extending inwardly and laterally from and fixed to the cam, said hub receiving said shaft, a sleeve extending radially from the lateral portion of said hub and fixed thereto, a member adjustable in the sleeve to engage and disengage the shaft for locking or releasing the hub in respect to the shaft, a lever having a slot therein in which the cam is movable, said lever being disposed below the hub and shaft, and a.

roller mounted in the slot of the lever to have engagement with the inner periphery of the cam so that when the lever is depressed the cam will be rotated about the'shaft as a center, and means for urging the lever to a position in which the roller is out ofengagement with the cam.

3. In a station selector mechanism, a rotary cam, a member urged to one extreme position and manually movable to another, an operative connection between said cam and member by which the cam is moved to a predetermined position, said operative connection being so correlatedto the cam and member as to permit the member to return to its urged position withoutdisturbing the position of the cam to which it has been moved, and means for mounting said member to permit adjustment thereof to effect an adjustment of the cam when in said predetermined position through said operative connection.

d. A station selector mechanism, comprising a plurality of separate and independent means acting upon operation to adjust a tuning instrument, means common to all the first means by which any one of the latter canbe adjusted to secure an additional adjustment of the tuning instrument following operation of the respective first means, and means for urging the second said means to an inactive position;

5. A station selector mechanism, comprising a plurality of separate and independent means actmeanest eration of the respective first means, and means for urging the single means to an inactive position so that when released from an active position it will return to inactive position to permit additional adjustment of any one of the first means.

6. A station selector mechanism, comprising a plurality of separate and independent means acting upon operation to adjust a tuning instrument. a single means operable to adjust any one of the first means to secure an additional adjustment of the tuning instrument following operation of any one of said means, means for urging the single means to a neutral position, and a switch urged to closed position and operatively connected to all of the first means so as to be moved to open position upon operation of any one of the first means.

7. A station selector mechanism, a shaft adapted for connection to a tuning instrument, a plurality of cams on the shaft, a plurality of levers acting when operated to engage and move the cams to secure predetermined degrees of rotation of said shaft, a cam shaft upon which said levers therein, and a spring having parts disposed in, a said slots and urged against the walls of the confronting ends of said slots, said spring parts having extensions disposed at opposite sides of said arm but normally out of contact therewith, and so as to be disposed in the path of movement of the arm in either direction to yleldingly oppose movement of the arm.

9. In a station selector mechanism as embodied in claim 7, wherein said means comprises an arm fixed to the cam shaft, a bracket having slots therein, and a spring having parts disposed in said slots and urged against the walls of the confronting ends of said slots, said spring parts having extensions disposed at opposite sides of said arm but normally out of contact therewith, and so as to be disposed in the path of movement of the arm in either direction to yieldingly oppose movement of the arm, and means operating to yieldably urge the cam shaft to a neutral position with respect to said levers, and the arm to a position between the ends of said extensions but out of contact therewith.

10. A station selector mechanism comprising: a plurality of adjusting units each including a cam and a member operatively associated with the cam and movable from one position to another to move the cam to a predetermined position for effecting a predetermined adjustment of a tuning instrument; and means common to all the members for so adjusting the latter that when the member of any unit occupies the second mentioned position, such adjustment will be transmitted to the respective cam so as to effect an additional adjustment of the tuning instrument.

11. A station selector mechanism comprising a plurality of means including levers selectively operable to effect a predetermined adjustment of a tuning instrument: a shaft having an eccentric portion on which the levers are mounted; and a member for rotating the shaft to cause the eccentric portion of the latter to coact with an operated one of the levers in effecting an additional adjustment of the tuning instrument.

12. A station selector mechanism comprising a plurality of means selectively operable to efiect a predetermined adjustment of a tuning instru- 

